Inclosed-screen ball-mill



J. R. BALL.

INCLOSED SCREEN BALL MILL.

. I APPLICATION FILED APR. 24, 1919. 1,337,033.- Pa ented Apr. 13, 1920.

2 SHEETS-SHEET 1.

J. R. BALL.

INCLOSED SCREEN BALL MILL.

APPHCATION FILED APR.24, 1919.

' Patented Apr. 13, 1920.

2 SHEETS-SHEET 2.

JOHN R. BALL, 0F DURANGO, COLORADO.

INCLOSED-SCREEN BALL-MILL.

Specification of Letters Patent.

Patented Apr. 13, 1920.

Application filed April 24, 1919. Serial No. 292,343.

the invention, such as will enable others skilled in the art to which itappertains to make and use the same.

My invention relates to that class of ore' grinding mills commonl knownas ball mills. Heretofore -mach1nes of this type have been. providedhaving passages for discharging the ground ore from the discharge screeninto a'hollow trunnion from which final discharge takes'place, but inall of such mills with which I am familiar, the screen has been entirelyaccessible only from the interior of the mill, for repairing whennecessary or for the installation of a new screen. This usually requiresthat a large part of the mill shall be torn down, thus necessitatingthat it be idle for considerable time which means great loss in time andoutput. The principal object of my invention is to overcome thisdifficulty by providing screens which are totally accessible from theexterior of the mill by simply removing a cover-plate, and it has beenfound that by this arrangement, the screen can be replaced (gr repairedin less than half the time previously required.

The grinding cylinder is provided on its discharge end with a pluralityof radial reinforcing ribs extending from the hub to the periphery, andanother object of the invention is to utilize these ribs, together witha removable plate or plates, to form independent pockets into which thescreens discharge the pulverized ore.

With the foregoing in view, the invention resides in the novel featuresof construction and unique association of parts hereinafter fullydescribed and claimed, reference being made to the accompanyingdrawings.

Figure 1 is a side elevation with parts broken away and in sect-ion toshow the improved features.

Fig. 2 is an end elevation of the grinding cylinder removed from itsbearings, parts being broken away and in section.

In the drawings above briefly described, the numeral 1 designates arotating cylinder of a ball mill, one end of such cylinder having atrunnion 2 supported in a bearing 3 and provided with the usual spiralcollecting head 4: which raises the ore laden slime and feeds the. sameinto the cylinder 1 through the trunnion 2, no claim being made in thepresent application to any of these parts.

The numeral 5 designates the end wall of the cylinder 1 opposite thetrunnion 2, said, end wall having a hollow trunnion shown as including ahub (3 integral with said wall and provided with an annular outstandingflange 7 to which the inner end of a detachable trunnion member 8 issecured by bolts or the like 9. The outer side of the end wall 5 isprovided with a plurality of radial ribs 10 leading from the hub 6 tothe peripheral portion of said plate for reinforcing the same, andscreens 11 are provided in the plate 5 betweenthe several ribs, saidscreens being detachably secured in place by any preferred means such asthe plates 12 and screws 13 shown. The inner sides of the screens maywell abut an end lining 11 on opposite sides of said ribs, and ifdesired the platesl? may be additionally secured to the peripheral edgeof the plate 14 by other screws 20. The ribs 10, the plate 14, and theplates 17 cooperate to form a plurality of radial pockets 21 into whichthe ground ore is discharged through the screens 11, and by meansofopenings 22 in the hollow hub 6, said pockets discharge such ore intothe hollow trunnion, from which the final discharge takes place. A tube23 forming a core is shown in the hollow trunnion 68, the periphery ofsaid core having longitudinal grooves 24 registering at their inner endswith the openings 22, to receive the discharged ore and carry it to theouter endof the trunnion 68. Core 23 is preferably hollow to decreaseweight.

By the construction shown and described, whenever it is necessary torepair or replace any of the screens 11, access thereto may be quicklyand easily had by removing the plate 14 and possibly the end plates 17,so that little time is necessary, with the result that the mill need notbe out of operation for any appreciable time. This is a highly importantadvantage as is also the ease with which access may be had to the,screens.

Since probably the best results are obtained from the details disclosed,they may well be followed, but within the scopeof the invention asclaimed, minor changes may well be made. Also, it will be understoodthat the form of screen may vary and that it may be of any requiredmesh. Furthermore, the mill may be used for grinding cement and numerousother materials as well as ore.

1. In an ore grinding mill, a grinding cylinder having a hollow trunnionjoined directly to one of its end walls, reinforcing ribs on the outerside of said end wall radiating from the inner end of said'trunnion,discharge screens between said ribs, plate means spaced outwardly fromsaid end wall and free of permanent connection with said trunnion, saidplate means being detachably secured at the outer edges of said ribs,and additional plate means extending across the ing ribs on the outerside of said wall and radiating from said hub, screens between saidribs, plate means secured to the outer edges of said ribs and extendingbetween them, additional plate means between the outer ends of the ribs,all of said plate means cooperating with said ribs to form pockets intowhich the screens discharge, the hub having openings leading from saidpockets into itsinterior, and a tubular trunnion member extendingoutwardly from said hub.

In testimony whereof I have hereunto set my hand.

JOHN R. BALL.

